"The unjustly spilled blood of this oppressed martyr will no doubt soon show its effect and divine vengeance will befall Saudi politicians.”

That rather ominous quote is from Ayatollah Khamenei who was decidedly upset with Saudi Arabia’s execution of prominent Shiite cleric Nimr al-Nimr.

The Sheikh - who died along with three other Shiites and dozens of suspected al-Qaeda operatives in the largest mass execution carried out by Riyadh in 25 years - was a leading voice in Saudi Arabia’s anti-government movement. He stood accused of sedition, disobedience and bearing arms for his role in the protests which shook the kingdom’s Eastern Province during the Arab Spring.

News of al-Nimr’s death spread through the Muslim world like wildfire on Saturday as protests broke out from Bahrain to Pakistan.

Saudi Arabia announced it had executed 47 people for terrorism, including the prominent Shia cleric Sheikh Nimr al-Nimr.

Iranian government and religious leaders say killing of Sheikh Nimr al-Nimr will have serious repercussions.

The Shia cleric’s brother calls for calm.

Protests in Bahrain turn violent and tear gas is used on those demonstrating.

Protests break out in Shia areas of Saudi Arabia, Indian-controlled Kashmir and Pakistan while a prominent Iraqi cleric calls for demonstrations in Gulf countries.

Reprieve, Human Rights Watch and various other campaign groups condemn the executions.

Fresh concerns are raised for Nimr’s nephew, Ali Mohammed al-Nimr, despite his name not appearing on the executed list.

As the day wore on, the situation escalated in Tehran, reaching a crescendo when angry protesters stormed the Saudi embassy before ultimately firebombing the compound. We documented the drama as it unfolded (see here), but below, find a few more visuals from the scene:

President Hassan Rouhani condemned the attacks as the work of "extremist individuals" while Tehran's police chief confirmed that a number of "unruly elements" had been detained in connection with the ransacking of the embassy. That said, it's probably safe to say that no one in Iran was all that upset to see the building set ablaze as al-Nimr's execution was something of a direct slap in the face to the Shiite community writ large.

"Nimr, the most vocal critic of the dynasty among the Shi'ite minority, had come to be seen as a leader of the sect's younger activists, who had tired of the failure of older, more measured leaders to achieve equality with Sunnis," Reuters writes adding that al-Nimr's death "appeared to end any hopes that the appearance of a common enemy in the form of the Islamic State militant force would produce some rapprochement between the region's leading Sunni and Shi'ite Muslim powers, allied to opposing sides in wars currently raging in Syria and Yemen." Here's The New York Times:

Sheikh Nimr, said to be in his mid-50s, was from Awamiyah, a poor town surrounded by palm groves in eastern Saudi Arabia and known for opposition to the monarchy.

He studied in Iran and Syria, but rose to prominence for fiery sermons after his return in which he criticized the ruling family and called for Shiite empowerment, even suggesting that Shiites could secede from the kingdom.

This gained him a following mostly among young Shiites who felt discriminated against by Persian Gulf governments. When these young people joined Arab Spring protests in Bahrain and eastern Saudi Arabia in 2011, Sheikh Nimr became a leading figure.

During a sermon in 2012, Sheikh Nimr mocked Prince Nayef bin Abdulaziz, who had been the Saudi interior minister and had recently died.

“He will be eaten by worms and suffer the torments of hell in the grave,” Sheikh Nimr said. “The man who made us live in fear and terror; shouldn’t we rejoice at his death?”

Prince Nayef’s son, Mohammed bin Nayef, is now the crown prince and runs the Interior Ministry, which carries out death sentences.

The Saudi authorities arrested Sheikh Nimr in July 2012, while the kingdom was leading a regional push to end the pro-democratic activism of the Arab Spring. These efforts included sending tanks to prop up the Sunni monarchy in Bahrain, which faced protests led by the country’s Shiite majority. Shiites also protested in Saudi Arabia’s oil-rich Eastern Province, where many Shiites live and complain of discrimination.

Nimr, executed along with three other Shi'ites and dozens of al Qaeda members, is seen in Iran as the champion of a Shi'ite minority oppressed in Saudi Arabia, and Tehran had made clear that it saw the terrorism charges against him as fabricated.

Iran summoned the Saudi charge d'affaires in Tehran, accusing the kingdom of using terrorism as a pretext to suppress peaceful dissent among Shi'ites, who complain of systemic discrimination.

And the website of Iran's Supreme Leader, Ayatollah Ali Khamenei, carried a picture of a Saudi executioner next to notorious Islamic State executioner 'Jihadi John', with the caption "Any differences?".

The fact that both Saudi Arabia and Iran face a powerful threat to their interests from the radical jihadist group, which has seized large parts of Syria and Iraq, appeared at the end of 2014 to be promoting a tentative reconciliation.

But since then, the political and economic tensions have been piling up.

Already backing opposing sides in Syria's civil war, they also found themselves backing rival groups in Saudi Arabia's impoverished neighbour Yemen, where Iran supports another minority Shi'ite group, the Houthis, who drove out the Saudi-backed government.

Economic rivalry has also come to the fore since Iran signed a nuclear deal with world powers in July that Saudi Arabia had urged its long-standing ally and protector, the United States, to block.

Yes, no hope a "common enemy" in ISIS will "produce some rapproachement" between Sunni and Shiite powers. Of course it also didn't help that the Saudis left Shiite Iran and Shiite Iraq out of a new, 34-nation anti-terror "coalition", nor does it help that Riyadh promotes and promulgates the very same ideology as that espoused by ISIS and al-Qaeda.

Iraq - which, as we've documented extensively, is for all intents and purposes an Iranian colony - was displeased as well. Here's Iraq's top Shi'ite cleric Grand Ayatollah Ali al-Sistani: "We have received with much sorrow and regret the news of the martyrdom of a number of our brother believers in the region whose pure blood was shed in an unjust aggression." And here's PM Haider Abadi:

I'm shocked & saddened at Sheikh Nimr's execution by Saudi authorities. Peaceful opposition is a fundamental right. Repression does not last

On Sunday, the protests continued as hundreds gathered in front of the charred Saudi embassy in Tehran while protesters also massed at the UN building and Riyadh's embassy in Beirut ahead of a speech by Hassan Nasrallah. As AP reports, "the road the embassy sits on in northern Tehran saw a new street sign come up in recent hours. Instead of saying "Boustan" or "park" in Farsi, it now reads "Sheikh Nimr St." in honor of the Shiite cleric that Saudi Arabia executed on Saturday."

So, to the extent Riyadh thought the execution of a few dozen purported al-Qaeda operatives would prove that the kingdom is serious about fighting the very same type of extremism it promotes, the exact opposite has occurred. That is, the executions have simply provided further evidence that the Saudis, like Islamic State, have no qualms about beheading "criminals" without any semblance of due process.

"Nimr's execution risks exacerbating sectarian tensions at a time when they urgently need to be reduced," the US State Department said of the Sheikh's death. While that is most assuredly an accurate assessment, the idea that Washington is concerned about fanning the flames of sectarian violence is laughable. Recall the following excerpt from a leaked diplomatic cable outlining what America's strategy should be in Syria:

PLAY ON SUNNI FEARS OF IRANIAN INFLUENCE: There are fears in Syria that the Iranians are active in both Shia proselytizing and conversion of, mostly poor, Sunnis. Though often exaggerated, such fears reflect an element of the Sunni community in Syria that is increasingly upset by and focused on the spread of Iranian influence in their country through activities ranging from mosque construction to business. Both the local Egyptian and Saudi missions here, (as well as prominent Syrian Sunni religious leaders), are giving increasing attention to the matter and we should coordinate more closely with their governments on ways to better publicize and focus regional attention on the issue.

Finally, we would note once again that just about the last thing the Saudis need is a Shiite uprising just as a move to cut subsidies on everything from fuel to water threatens to destabilize a populace that's become accustomed to a relatively comfortable way of life under the oil-rich monarchy.

We close with the following image which appeared on the Ayatollah's webpage:

* * *

Full statement from Khamenei

Ayatollah Seyyed Ali Khamenei, the Leader of the Islamic Revolution, at the start of his course to clerics at the post-jurisprudence level on Sunday morning, strongly condemned Saudi Arabia’s major crime in martyring the pious and innocent scholar, Sheikh Nimr Baqir al-Nimr. Underscoring the necessity for the international community to feel responsibility vis-à-vis this crime and similar crimes committed by the Saudi regime in Yemen and Bahrain, Ayatollah Khamenei noted: “Doubtlessly, this innocent martyr’s blood, which was spilled unjustly, will quickly show its effect and the divine vengeance will befall the Saudi politicians.”

Ayatollah Khamenei added: “This innocent scholar had neither incited people to take up arms nor had he hatched any covert plot, and the only activity he did was open criticism [of the Saudi regime] and ordering good and prohibiting vice, which stemmed from his religious zeal and fervor.”

The Leader of the Islamic Revolution described Sheikh Nimr’s martyrdom and the unjust spilling of his blood as a political mistake made by the Saudi government, saying: “The Almighty God shall not ignore the innocents’ blood and the unjustly spilled blood will backfire on the politicians and the executives of this regime very quickly.”

Strongly criticizing the silence of the self-proclaimed advocates of freedom, democracy and human rights, and their support for the Saudi regime, who spills the blood of the innocent only for criticism and protest, Ayatollah Khamenei said: “The Muslim world and the entire world must feel responsible towards this issue.”

Ayatollah Khamenei also mentioned the harassment and torture of Bahraini people by the Saudi military forces and the destruction of their houses and mosques as well as more than 10 months of bombing of the Yemeni civilians as other examples of the Saudi regime’s crimes, noting: “Those who honestly care for the future of humanity and the fate of human rights and justice must pursue these issues and should not remain indifferent vis-à-vis this situation.”

The Leader of the Islamic Revolution also stated: “Definitely, Martyr Sheikh Nimr will avail himself of the Grace of God and without a doubt the divine vengeance will befall the oppressors, who encroached upon his life and this is the same thing that will be a cause of consolation.”